Move library source into src sub-directory

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 304 insertions, 0 deletions

diff --git a/lib/tar/src/read_header.c b/lib/tar/src/read_header.c
new file mode 100644
index 0000000..ea4873b
--- /dev/null
+++ b/lib/tar/src/read_header.c
@@ -0,0 +1,304 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * read_header.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "internal.h"
+#include <string.h>
+#include <stdlib.h>
+
+static bool is_zero_block(const tar_header_t *hdr)
+{
+	const unsigned char *ptr = (const unsigned char *)hdr;
+
+	return ptr[0] == '\0' && memcmp(ptr, ptr + 1, sizeof(*hdr) - 1) == 0;
+}
+
+static int check_version(const tar_header_t *hdr)
+{
+	char buffer[sizeof(hdr->magic) + sizeof(hdr->version)];
+
+	memset(buffer, '\0', sizeof(buffer));
+	if (memcmp(hdr->magic, buffer, sizeof(hdr->magic)) == 0 &&
+	    memcmp(hdr->version, buffer, sizeof(hdr->version)) == 0)
+		return ETV_V7_UNIX;
+
+	if (memcmp(hdr->magic, TAR_MAGIC, sizeof(hdr->magic)) == 0 &&
+	    memcmp(hdr->version, TAR_VERSION, sizeof(hdr->version)) == 0)
+		return ETV_POSIX;
+
+	if (memcmp(hdr->magic, TAR_MAGIC_OLD, sizeof(hdr->magic)) == 0 &&
+	    memcmp(hdr->version, TAR_VERSION_OLD, sizeof(hdr->version)) == 0)
+		return ETV_PRE_POSIX;
+
+	return ETV_UNKNOWN;
+}
+
+static int decode_header(const tar_header_t *hdr, unsigned int set_by_pax,
+			 tar_header_decoded_t *out, int version)
+{
+	size_t len1, len2;
+	sqfs_u64 field;
+
+	if (!(set_by_pax & PAX_NAME)) {
+		if (hdr->tail.posix.prefix[0] != '\0' &&
+		    version == ETV_POSIX) {
+			len1 = strnlen(hdr->name, sizeof(hdr->name));
+			len2 = strnlen(hdr->tail.posix.prefix,
+				       sizeof(hdr->tail.posix.prefix));
+
+			out->name = malloc(len1 + 1 + len2 + 1);
+
+			if (out->name != NULL) {
+				memcpy(out->name, hdr->tail.posix.prefix, len2);
+				out->name[len2] = '/';
+				memcpy(out->name + len2 + 1, hdr->name, len1);
+				out->name[len1 + 1 + len2] = '\0';
+			}
+		} else {
+			out->name = strndup(hdr->name, sizeof(hdr->name));
+		}
+
+		if (out->name == NULL) {
+			perror("decoding filename");
+			return -1;
+		}
+	}
+
+	if (!(set_by_pax & PAX_SIZE)) {
+		if (read_number(hdr->size, sizeof(hdr->size), &out->record_size))
+			return -1;
+	}
+
+	if (!(set_by_pax & PAX_UID)) {
+		if (read_number(hdr->uid, sizeof(hdr->uid), &field))
+			return -1;
+		out->uid = field;
+	}
+
+	if (!(set_by_pax & PAX_GID)) {
+		if (read_number(hdr->gid, sizeof(hdr->gid), &field))
+			return -1;
+		out->gid = field;
+	}
+
+	if (!(set_by_pax & PAX_DEV_MAJ)) {
+		if (read_number(hdr->devmajor, sizeof(hdr->devmajor), &field))
+			return -1;
+
+		out->devno = makedev(field, minor(out->devno));
+	}
+
+	if (!(set_by_pax & PAX_DEV_MIN)) {
+		if (read_number(hdr->devminor, sizeof(hdr->devminor), &field))
+			return -1;
+
+		out->devno = makedev(major(out->devno), field);
+	}
+
+	if (!(set_by_pax & PAX_MTIME)) {
+		if (read_number(hdr->mtime, sizeof(hdr->mtime), &field))
+			return -1;
+		if (field & 0x8000000000000000UL) {
+			field = ~field + 1;
+			out->mtime = -((sqfs_s64)field);
+		} else {
+			out->mtime = field;
+		}
+	}
+
+	if (read_octal(hdr->mode, sizeof(hdr->mode), &field))
+		return -1;
+
+	out->mode = field & 07777;
+
+	if (hdr->typeflag == TAR_TYPE_LINK ||
+	    hdr->typeflag == TAR_TYPE_SLINK) {
+		if (!(set_by_pax & PAX_SLINK_TARGET)) {
+			out->link_target = strndup(hdr->linkname,
+						   sizeof(hdr->linkname));
+			if (out->link_target == NULL) {
+				perror("decoding symlink target");
+				return -1;
+			}
+		}
+	}
+
+	out->unknown_record = false;
+
+	switch (hdr->typeflag) {
+	case '\0':
+	case TAR_TYPE_FILE:
+	case TAR_TYPE_GNU_SPARSE:
+		out->mode |= S_IFREG;
+		break;
+	case TAR_TYPE_LINK:
+		out->is_hard_link = true;
+		break;
+	case TAR_TYPE_SLINK:
+		out->mode = S_IFLNK | 0777;
+		break;
+	case TAR_TYPE_CHARDEV:
+		out->mode |= S_IFCHR;
+		break;
+	case TAR_TYPE_BLOCKDEV:
+		out->mode |= S_IFBLK;
+		break;
+	case TAR_TYPE_DIR:
+		out->mode |= S_IFDIR;
+		break;
+	case TAR_TYPE_FIFO:
+		out->mode |= S_IFIFO;
+		break;
+	default:
+		out->unknown_record = true;
+		break;
+	}
+
+	return 0;
+}
+
+int read_header(istream_t *fp, tar_header_decoded_t *out)
+{
+	unsigned int set_by_pax = 0;
+	bool prev_was_zero = false;
+	sqfs_u64 pax_size;
+	tar_header_t hdr;
+	int version, ret;
+
+	memset(out, 0, sizeof(*out));
+
+	for (;;) {
+		ret = istream_read(fp, &hdr, sizeof(hdr));
+		if (ret < 0)
+			goto fail;
+
+		if ((size_t)ret < sizeof(hdr))
+			goto out_eof;
+
+		if (is_zero_block(&hdr)) {
+			if (prev_was_zero)
+				goto out_eof;
+			prev_was_zero = true;
+			continue;
+		}
+
+		prev_was_zero = false;
+		version = check_version(&hdr);
+
+		if (version == ETV_UNKNOWN)
+			goto fail_magic;
+
+		if (!is_checksum_valid(&hdr))
+			goto fail_chksum;
+
+		switch (hdr.typeflag) {
+		case TAR_TYPE_GNU_SLINK:
+			if (read_number(hdr.size, sizeof(hdr.size), &pax_size))
+				goto fail;
+			if (pax_size < 1 || pax_size > TAR_MAX_SYMLINK_LEN)
+				goto fail_slink_len;
+			free(out->link_target);
+			out->link_target = record_to_memory(fp, pax_size);
+			if (out->link_target == NULL)
+				goto fail;
+			set_by_pax |= PAX_SLINK_TARGET;
+			continue;
+		case TAR_TYPE_GNU_PATH:
+			if (read_number(hdr.size, sizeof(hdr.size), &pax_size))
+				goto fail;
+			if (pax_size < 1 || pax_size > TAR_MAX_PATH_LEN)
+				goto fail_path_len;
+			free(out->name);
+			out->name = record_to_memory(fp, pax_size);
+			if (out->name == NULL)
+				goto fail;
+			set_by_pax |= PAX_NAME;
+			continue;
+		case TAR_TYPE_PAX_GLOBAL:
+			if (read_number(hdr.size, sizeof(hdr.size), &pax_size))
+				goto fail;
+			skip_entry(fp, pax_size);
+			continue;
+		case TAR_TYPE_PAX:
+			clear_header(out);
+			if (read_number(hdr.size, sizeof(hdr.size), &pax_size))
+				goto fail;
+			if (pax_size < 1 || pax_size > TAR_MAX_PAX_LEN)
+				goto fail_pax_len;
+			set_by_pax = 0;
+			if (read_pax_header(fp, pax_size, &set_by_pax, out))
+				goto fail;
+			continue;
+		case TAR_TYPE_GNU_SPARSE:
+			free_sparse_list(out->sparse);
+			out->sparse = read_gnu_old_sparse(fp, &hdr);
+			if (out->sparse == NULL)
+				goto fail;
+			if (read_number(hdr.tail.gnu.realsize,
+					sizeof(hdr.tail.gnu.realsize),
+					&out->actual_size))
+				goto fail;
+			break;
+		default:
+			break;
+		}
+		break;
+	}
+
+	if (decode_header(&hdr, set_by_pax, out, version))
+		goto fail;
+
+	if (set_by_pax & PAX_SPARSE_GNU_1_X) {
+		free_sparse_list(out->sparse);
+		out->sparse = read_gnu_new_sparse(fp, out);
+		if (out->sparse == NULL)
+			goto fail;
+	}
+
+	if (out->sparse == NULL)
+		out->actual_size = out->record_size;
+
+	return 0;
+out_eof:
+	clear_header(out);
+	return 1;
+fail_slink_len:
+	fprintf(stderr, "rejecting GNU symlink header with size %lu\n",
+		(unsigned long)pax_size);
+	goto fail;
+fail_path_len:
+	fprintf(stderr, "rejecting GNU long path header with size %lu\n",
+		(unsigned long)pax_size);
+	goto fail;
+fail_pax_len:
+	fprintf(stderr, "rejecting PAX header with size %lu\n",
+		(unsigned long)pax_size);
+	goto fail;
+fail_magic:
+	fputs("input is not a ustar tar archive!\n", stderr);
+	goto fail;
+fail_chksum:
+	fputs("invalid tar header checksum!\n", stderr);
+	goto fail;
+fail:
+	clear_header(out);
+	return -1;
+}
+
+int skip_padding(istream_t *fp, sqfs_u64 size)
+{
+	size_t tail = size % 512;
+
+	return tail ? istream_skip(fp, 512 - tail) : 0;
+}
+
+int skip_entry(istream_t *fp, sqfs_u64 size)
+{
+	size_t tail = size % 512;
+
+	return istream_skip(fp, tail ? (size + 512 - tail) : size);
+}